Prior art fluid operated torque converter clutches use spring type dampers, viscous dampers or viscous clutches in series with the fluid operated friction clutch portion, to control the prevention of transmitting engine torsional vibrations.
With the viscous and friction clutch combination, it has been proposed to provide a bypass clutch which is effective to eliminate the viscous clutch under certain conditions.
It is also well known with the prior art devices that internal temperatures of the viscous portion will reduce the torque capacity or gain function of the viscous portion of the clutch. Generally to prevent increase of temperature within the viscous fluid, a multitude of cooling passages are provided, such that the torque converter fluid can be utilized to cool the viscous portion of the clutch.